package com.clark.lang;

import static com.clark.func.Functions.contains;

import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Collection;
import java.util.Comparator;

/**
 * Assists in implementing {@link java.lang.Comparable#compareTo(Object)}
 * methods.
 * 
 * It is consistent with <code>equals(Object)</code> and <code>hashcode()</code>
 * built with {@link EqualsBuilder} and {@link HashCodeBuilder}.</p>
 * 
 * <p>
 * Two Objects that compare equal using <code>equals(Object)</code> should
 * normally also compare equal using <code>compareTo(Object)</code>.
 * </p>
 * 
 * <p>
 * All relevant fields should be included in the calculation of the comparison.
 * Derived fields may be ignored. The same fields, in the same order, should be
 * used in both <code>compareTo(Object)</code> and <code>equals(Object)</code>.
 * </p>
 * 
 * <p>
 * To use this class write code as follows:
 * </p>
 * 
 * <pre>
 * public class MyClass {
 *   String field1;
 *   int field2;
 *   boolean field3;
 * 
 *   ...
 * 
 *   public int compareTo(Object o) {
 *     MyClass myClass = (MyClass) o;
 *     return new CompareToBuilder()
 *       .appendSuper(super.compareTo(o)
 *       .append(this.field1, myClass.field1)
 *       .append(this.field2, myClass.field2)
 *       .append(this.field3, myClass.field3)
 *       .toComparison();
 *   }
 * }
 * </pre>
 * 
 * <p>
 * Alternatively, there are {@link #reflectionCompare(Object, Object)
 * reflectionCompare} methods that use reflection to determine the fields to
 * append. Because fields can be private, <code>reflectionCompare</code> uses
 * {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} to bypass
 * normal access control checks. This will fail under a security manager, unless
 * the appropriate permissions are set up correctly. It is also slower than
 * appending explicitly.
 * </p>
 * 
 * <p>
 * A typical implementation of <code>compareTo(Object)</code> using
 * <code>reflectionCompare</code> looks like:
 * </p>
 * 
 * <pre>
 * public int compareTo(Object o) {
 *     return CompareToBuilder.reflectionCompare(this, o);
 * }
 * </pre>
 * 
 * @see java.lang.Comparable
 * @see java.lang.Object#equals(Object)
 * @see java.lang.Object#hashCode()
 * @see EqualsBuilder
 * @see HashCodeBuilder
 * @author Apache Software Foundation
 * @author <a href="mailto:steve.downey@netfolio.com">Steve Downey</a>
 * @author Gary Gregory
 * @author Pete Gieser
 * @since 1.0
 * @version $Id: CompareToBuilder.java 965941 2010-07-20 18:10:34Z bayard $
 */
public class CompareToBuilder implements Builder<Integer> {

    /**
     * Current state of the comparison as appended fields are checked.
     */
    private int comparison;

    /**
     * <p>
     * Constructor for CompareToBuilder.
     * </p>
     * 
     * <p>
     * Starts off assuming that the objects are equal. Multiple calls are then
     * made to the various append methods, followed by a call to
     * {@link #toComparison} to get the result.
     * </p>
     */
    public CompareToBuilder() {
        super();
        comparison = 0;
    }

    // -----------------------------------------------------------------------
    /**
     * <p>
     * Compares two <code>Object</code>s via reflection.
     * </p>
     * 
     * <p>
     * Fields can be private, thus <code>AccessibleObject.setAccessible</code>
     * is used to bypass normal access control checks. This will fail under a
     * security manager unless the appropriate permissions are set.
     * </p>
     * 
     * <ul>
     * <li>Static fields will not be compared</li>
     * <li>Transient members will be not be compared, as they are likely derived
     * fields</li>
     * <li>Superclass fields will be compared</li>
     * </ul>
     * 
     * <p>
     * If both <code>lhs</code> and <code>rhs</code> are <code>null</code>, they
     * are considered equal.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @return a negative integer, zero, or a positive integer as
     *         <code>lhs</code> is less than, equal to, or greater than
     *         <code>rhs</code>
     * @throws NullPointerException
     *             if either (but not both) parameters are <code>null</code>
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     */
    public static int reflectionCompare(Object lhs, Object rhs) {
        return reflectionCompare(lhs, rhs, false, null, null);
    }

    /**
     * <p>
     * Compares two <code>Object</code>s via reflection.
     * </p>
     * 
     * <p>
     * Fields can be private, thus <code>AccessibleObject.setAccessible</code>
     * is used to bypass normal access control checks. This will fail under a
     * security manager unless the appropriate permissions are set.
     * </p>
     * 
     * <ul>
     * <li>Static fields will not be compared</li>
     * <li>If <code>compareTransients</code> is <code>true</code>, compares
     * transient members. Otherwise ignores them, as they are likely derived
     * fields.</li>
     * <li>Superclass fields will be compared</li>
     * </ul>
     * 
     * <p>
     * If both <code>lhs</code> and <code>rhs</code> are <code>null</code>, they
     * are considered equal.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @param compareTransients
     *            whether to compare transient fields
     * @return a negative integer, zero, or a positive integer as
     *         <code>lhs</code> is less than, equal to, or greater than
     *         <code>rhs</code>
     * @throws NullPointerException
     *             if either <code>lhs</code> or <code>rhs</code> (but not both)
     *             is <code>null</code>
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     */
    public static int reflectionCompare(Object lhs, Object rhs,
            boolean compareTransients) {
        return reflectionCompare(lhs, rhs, compareTransients, null, null);
    }

    /**
     * <p>
     * Compares two <code>Object</code>s via reflection.
     * </p>
     * 
     * <p>
     * Fields can be private, thus <code>AccessibleObject.setAccessible</code>
     * is used to bypass normal access control checks. This will fail under a
     * security manager unless the appropriate permissions are set.
     * </p>
     * 
     * <ul>
     * <li>Static fields will not be compared</li>
     * <li>If <code>compareTransients</code> is <code>true</code>, compares
     * transient members. Otherwise ignores them, as they are likely derived
     * fields.</li>
     * <li>Superclass fields will be compared</li>
     * </ul>
     * 
     * <p>
     * If both <code>lhs</code> and <code>rhs</code> are <code>null</code>, they
     * are considered equal.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @param excludeFields
     *            Collection of String fields to exclude
     * @return a negative integer, zero, or a positive integer as
     *         <code>lhs</code> is less than, equal to, or greater than
     *         <code>rhs</code>
     * @throws NullPointerException
     *             if either <code>lhs</code> or <code>rhs</code> (but not both)
     *             is <code>null</code>
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     * @since 2.2
     */
    public static int reflectionCompare(Object lhs, Object rhs,
            Collection<String> excludeFields) {
        return reflectionCompare(lhs, rhs,
                ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
    }

    /**
     * <p>
     * Compares two <code>Object</code>s via reflection.
     * </p>
     * 
     * <p>
     * Fields can be private, thus <code>AccessibleObject.setAccessible</code>
     * is used to bypass normal access control checks. This will fail under a
     * security manager unless the appropriate permissions are set.
     * </p>
     * 
     * <ul>
     * <li>Static fields will not be compared</li>
     * <li>If <code>compareTransients</code> is <code>true</code>, compares
     * transient members. Otherwise ignores them, as they are likely derived
     * fields.</li>
     * <li>Superclass fields will be compared</li>
     * </ul>
     * 
     * <p>
     * If both <code>lhs</code> and <code>rhs</code> are <code>null</code>, they
     * are considered equal.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @param excludeFields
     *            array of fields to exclude
     * @return a negative integer, zero, or a positive integer as
     *         <code>lhs</code> is less than, equal to, or greater than
     *         <code>rhs</code>
     * @throws NullPointerException
     *             if either <code>lhs</code> or <code>rhs</code> (but not both)
     *             is <code>null</code>
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     * @since 2.2
     */
    public static int reflectionCompare(Object lhs, Object rhs,
            String[] excludeFields) {
        return reflectionCompare(lhs, rhs, false, null, excludeFields);
    }

    /**
     * <p>
     * Compares two <code>Object</code>s via reflection.
     * </p>
     * 
     * <p>
     * Fields can be private, thus <code>AccessibleObject.setAccessible</code>
     * is used to bypass normal access control checks. This will fail under a
     * security manager unless the appropriate permissions are set.
     * </p>
     * 
     * <ul>
     * <li>Static fields will not be compared</li>
     * <li>If the <code>compareTransients</code> is <code>true</code>, compares
     * transient members. Otherwise ignores them, as they are likely derived
     * fields.</li>
     * <li>Compares superclass fields up to and including
     * <code>reflectUpToClass</code>. If <code>reflectUpToClass</code> is
     * <code>null</code>, compares all superclass fields.</li>
     * </ul>
     * 
     * <p>
     * If both <code>lhs</code> and <code>rhs</code> are <code>null</code>, they
     * are considered equal.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @param compareTransients
     *            whether to compare transient fields
     * @param reflectUpToClass
     *            last superclass for which fields are compared
     * @return a negative integer, zero, or a positive integer as
     *         <code>lhs</code> is less than, equal to, or greater than
     *         <code>rhs</code>
     * @throws NullPointerException
     *             if either <code>lhs</code> or <code>rhs</code> (but not both)
     *             is <code>null</code>
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     * @since 2.0
     */
    public static int reflectionCompare(Object lhs, Object rhs,
            boolean compareTransients, Class<?> reflectUpToClass) {
        return reflectionCompare(lhs, rhs, compareTransients, reflectUpToClass,
                null);
    }

    /**
     * <p>
     * Compares two <code>Object</code>s via reflection.
     * </p>
     * 
     * <p>
     * Fields can be private, thus <code>AccessibleObject.setAccessible</code>
     * is used to bypass normal access control checks. This will fail under a
     * security manager unless the appropriate permissions are set.
     * </p>
     * 
     * <ul>
     * <li>Static fields will not be compared</li>
     * <li>If the <code>compareTransients</code> is <code>true</code>, compares
     * transient members. Otherwise ignores them, as they are likely derived
     * fields.</li>
     * <li>Compares superclass fields up to and including
     * <code>reflectUpToClass</code>. If <code>reflectUpToClass</code> is
     * <code>null</code>, compares all superclass fields.</li>
     * </ul>
     * 
     * <p>
     * If both <code>lhs</code> and <code>rhs</code> are <code>null</code>, they
     * are considered equal.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @param compareTransients
     *            whether to compare transient fields
     * @param reflectUpToClass
     *            last superclass for which fields are compared
     * @param excludeFields
     *            fields to exclude
     * @return a negative integer, zero, or a positive integer as
     *         <code>lhs</code> is less than, equal to, or greater than
     *         <code>rhs</code>
     * @throws NullPointerException
     *             if either <code>lhs</code> or <code>rhs</code> (but not both)
     *             is <code>null</code>
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     * @since 2.2
     */
    public static int reflectionCompare(Object lhs, Object rhs,
            boolean compareTransients, Class<?> reflectUpToClass,
            String[] excludeFields) {

        if (lhs == rhs) {
            return 0;
        }
        if (lhs == null || rhs == null) {
            throw new NullPointerException();
        }
        Class<?> lhsClazz = lhs.getClass();
        if (!lhsClazz.isInstance(rhs)) {
            throw new ClassCastException();
        }
        CompareToBuilder compareToBuilder = new CompareToBuilder();
        reflectionAppend(lhs, rhs, lhsClazz, compareToBuilder,
                compareTransients, excludeFields);
        while (lhsClazz.getSuperclass() != null && lhsClazz != reflectUpToClass) {
            lhsClazz = lhsClazz.getSuperclass();
            reflectionAppend(lhs, rhs, lhsClazz, compareToBuilder,
                    compareTransients, excludeFields);
        }
        return compareToBuilder.toComparison();
    }

    /**
     * <p>
     * Appends to <code>builder</code> the comparison of <code>lhs</code> to
     * <code>rhs</code> using the fields defined in <code>clazz</code>.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @param clazz
     *            <code>Class</code> that defines fields to be compared
     * @param builder
     *            <code>CompareToBuilder</code> to append to
     * @param useTransients
     *            whether to compare transient fields
     * @param excludeFields
     *            fields to exclude
     */
    private static void reflectionAppend(Object lhs, Object rhs,
            Class<?> clazz, CompareToBuilder builder, boolean useTransients,
            String[] excludeFields) {

        Field[] fields = clazz.getDeclaredFields();
        AccessibleObject.setAccessible(fields, true);
        for (int i = 0; i < fields.length && builder.comparison == 0; i++) {
            Field f = fields[i];
            if (!contains(excludeFields, f.getName())
                    && (f.getName().indexOf('$') == -1)
                    && (useTransients || !Modifier
                            .isTransient(f.getModifiers()))
                    && (!Modifier.isStatic(f.getModifiers()))) {
                try {
                    builder.append(f.get(lhs), f.get(rhs));
                } catch (IllegalAccessException e) {
                    // This can't happen. Would get a Security exception
                    // instead.
                    // Throw a runtime exception in case the impossible happens.
                    throw new InternalError("Unexpected IllegalAccessException");
                }
            }
        }
    }

    // -----------------------------------------------------------------------
    /**
     * <p>
     * Appends to the <code>builder</code> the <code>compareTo(Object)</code>
     * result of the superclass.
     * </p>
     * 
     * @param superCompareTo
     *            result of calling <code>super.compareTo(Object)</code>
     * @return this - used to chain append calls
     * @since 2.0
     */
    public CompareToBuilder appendSuper(int superCompareTo) {
        if (comparison != 0) {
            return this;
        }
        comparison = superCompareTo;
        return this;
    }

    // -----------------------------------------------------------------------
    /**
     * <p>
     * Appends to the <code>builder</code> the comparison of two
     * <code>Object</code>s.
     * </p>
     * 
     * <ol>
     * <li>Check if <code>lhs == rhs</code></li>
     * <li>Check if either <code>lhs</code> or <code>rhs</code> is
     * <code>null</code>, a <code>null</code> object is less than a non-
     * <code>null</code> object</li>
     * <li>Check the object contents</li>
     * </ol>
     * 
     * <p>
     * <code>lhs</code> must either be an array or implement {@link Comparable}.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @return this - used to chain append calls
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     */
    public CompareToBuilder append(Object lhs, Object rhs) {
        return append(lhs, rhs, null);
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the comparison of two
     * <code>Object</code>s.
     * </p>
     * 
     * <ol>
     * <li>Check if <code>lhs == rhs</code></li>
     * <li>Check if either <code>lhs</code> or <code>rhs</code> is
     * <code>null</code>, a <code>null</code> object is less than a non-
     * <code>null</code> object</li>
     * <li>Check the object contents</li>
     * </ol>
     * 
     * <p>
     * If <code>lhs</code> is an array, array comparison methods will be used.
     * Otherwise <code>comparator</code> will be used to compare the objects. If
     * <code>comparator</code> is <code>null</code>, <code>lhs</code> must
     * implement {@link Comparable} instead.
     * </p>
     * 
     * @param lhs
     *            left-hand object
     * @param rhs
     *            right-hand object
     * @param comparator
     *            <code>Comparator</code> used to compare the objects,
     *            <code>null</code> means treat lhs as <code>Comparable</code>
     * @return this - used to chain append calls
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     * @since 2.0
     */
    public CompareToBuilder append(Object lhs, Object rhs,
            Comparator<?> comparator) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.getClass().isArray()) {
            // switch on type of array, to dispatch to the correct handler
            // handles multi dimensional arrays
            // throws a ClassCastException if rhs is not the correct array type
            if (lhs instanceof long[]) {
                append((long[]) lhs, (long[]) rhs);
            } else if (lhs instanceof int[]) {
                append((int[]) lhs, (int[]) rhs);
            } else if (lhs instanceof short[]) {
                append((short[]) lhs, (short[]) rhs);
            } else if (lhs instanceof char[]) {
                append((char[]) lhs, (char[]) rhs);
            } else if (lhs instanceof byte[]) {
                append((byte[]) lhs, (byte[]) rhs);
            } else if (lhs instanceof double[]) {
                append((double[]) lhs, (double[]) rhs);
            } else if (lhs instanceof float[]) {
                append((float[]) lhs, (float[]) rhs);
            } else if (lhs instanceof boolean[]) {
                append((boolean[]) lhs, (boolean[]) rhs);
            } else {
                // not an array of primitives
                // throws a ClassCastException if rhs is not an array
                append((Object[]) lhs, (Object[]) rhs, comparator);
            }
        } else {
            // the simple case, not an array, just test the element
            if (comparator == null) {
                @SuppressWarnings("unchecked")
                // assume this can be done; if not throw CCE as per Javadoc
                final Comparable<Object> comparable = (Comparable<Object>) lhs;
                comparison = comparable.compareTo(rhs);
            } else {
                @SuppressWarnings("unchecked")
                // assume this can be done; if not throw CCE as per Javadoc
                final Comparator<Object> comparator2 = (Comparator<Object>) comparator;
                comparison = comparator2.compare(lhs, rhs);
            }
        }
        return this;
    }

    // -------------------------------------------------------------------------
    /**
     * Appends to the <code>builder</code> the comparison of two
     * <code>long</code>s.
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(long lhs, long rhs) {
        if (comparison != 0) {
            return this;
        }
        comparison = ((lhs < rhs) ? -1 : ((lhs > rhs) ? 1 : 0));
        return this;
    }

    /**
     * Appends to the <code>builder</code> the comparison of two
     * <code>int</code>s.
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(int lhs, int rhs) {
        if (comparison != 0) {
            return this;
        }
        comparison = ((lhs < rhs) ? -1 : ((lhs > rhs) ? 1 : 0));
        return this;
    }

    /**
     * Appends to the <code>builder</code> the comparison of two
     * <code>short</code>s.
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(short lhs, short rhs) {
        if (comparison != 0) {
            return this;
        }
        comparison = ((lhs < rhs) ? -1 : ((lhs > rhs) ? 1 : 0));
        return this;
    }

    /**
     * Appends to the <code>builder</code> the comparison of two
     * <code>char</code>s.
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(char lhs, char rhs) {
        if (comparison != 0) {
            return this;
        }
        comparison = ((lhs < rhs) ? -1 : ((lhs > rhs) ? 1 : 0));
        return this;
    }

    /**
     * Appends to the <code>builder</code> the comparison of two
     * <code>byte</code>s.
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(byte lhs, byte rhs) {
        if (comparison != 0) {
            return this;
        }
        comparison = ((lhs < rhs) ? -1 : ((lhs > rhs) ? 1 : 0));
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the comparison of two
     * <code>double</code>s.
     * </p>
     * 
     * <p>
     * This handles NaNs, Infinities, and <code>-0.0</code>.
     * </p>
     * 
     * <p>
     * It is compatible with the hash code generated by
     * <code>HashCodeBuilder</code>.
     * </p>
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(double lhs, double rhs) {
        if (comparison != 0) {
            return this;
        }
        comparison = Double.compare(lhs, rhs);
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the comparison of two
     * <code>float</code>s.
     * </p>
     * 
     * <p>
     * This handles NaNs, Infinities, and <code>-0.0</code>.
     * </p>
     * 
     * <p>
     * It is compatible with the hash code generated by
     * <code>HashCodeBuilder</code>.
     * </p>
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(float lhs, float rhs) {
        if (comparison != 0) {
            return this;
        }
        comparison = Float.compare(lhs, rhs);
        return this;
    }

    /**
     * Appends to the <code>builder</code> the comparison of two
     * <code>booleans</code>s.
     * 
     * @param lhs
     *            left-hand value
     * @param rhs
     *            right-hand value
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(boolean lhs, boolean rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == false) {
            comparison = -1;
        } else {
            comparison = +1;
        }
        return this;
    }

    // -----------------------------------------------------------------------
    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>Object</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a short length array is less than a long length
     * array</li>
     * <li>Check array contents element by element using
     * {@link #append(Object, Object, Comparator)}</li>
     * </ol>
     * 
     * <p>
     * This method will also will be called for the top level of
     * multi-dimensional, ragged, and multi-typed arrays.
     * </p>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     */
    public CompareToBuilder append(Object[] lhs, Object[] rhs) {
        return append(lhs, rhs, null);
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>Object</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a short length array is less than a long length
     * array</li>
     * <li>Check array contents element by element using
     * {@link #append(Object, Object, Comparator)}</li>
     * </ol>
     * 
     * <p>
     * This method will also will be called for the top level of
     * multi-dimensional, ragged, and multi-typed arrays.
     * </p>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @param comparator
     *            <code>Comparator</code> to use to compare the array elements,
     *            <code>null</code> means to treat <code>lhs</code> elements as
     *            <code>Comparable</code>.
     * @return this - used to chain append calls
     * @throws ClassCastException
     *             if <code>rhs</code> is not assignment-compatible with
     *             <code>lhs</code>
     * @since 2.0
     */
    public CompareToBuilder append(Object[] lhs, Object[] rhs,
            Comparator<?> comparator) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i], comparator);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>long</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(long, long)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(long[] lhs, long[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>int</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(int, int)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(int[] lhs, int[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>short</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(short, short)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(short[] lhs, short[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>char</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(char, char)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(char[] lhs, char[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>byte</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(byte, byte)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(byte[] lhs, byte[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>double</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(double, double)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(double[] lhs, double[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>float</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(float, float)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(float[] lhs, float[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    /**
     * <p>
     * Appends to the <code>builder</code> the deep comparison of two
     * <code>boolean</code> arrays.
     * </p>
     * 
     * <ol>
     * <li>Check if arrays are the same using <code>==</code></li>
     * <li>Check if for <code>null</code>, <code>null</code> is less than non-
     * <code>null</code></li>
     * <li>Check array length, a shorter length array is less than a longer
     * length array</li>
     * <li>Check array contents element by element using
     * {@link #append(boolean, boolean)}</li>
     * </ol>
     * 
     * @param lhs
     *            left-hand array
     * @param rhs
     *            right-hand array
     * @return this - used to chain append calls
     */
    public CompareToBuilder append(boolean[] lhs, boolean[] rhs) {
        if (comparison != 0) {
            return this;
        }
        if (lhs == rhs) {
            return this;
        }
        if (lhs == null) {
            comparison = -1;
            return this;
        }
        if (rhs == null) {
            comparison = +1;
            return this;
        }
        if (lhs.length != rhs.length) {
            comparison = (lhs.length < rhs.length) ? -1 : +1;
            return this;
        }
        for (int i = 0; i < lhs.length && comparison == 0; i++) {
            append(lhs[i], rhs[i]);
        }
        return this;
    }

    // -----------------------------------------------------------------------
    /**
     * Returns a negative integer, a positive integer, or zero as the
     * <code>builder</code> has judged the "left-hand" side as less than,
     * greater than, or equal to the "right-hand" side.
     * 
     * @return final comparison result
     */
    public int toComparison() {
        return comparison;
    }

    /**
     * Returns a negative integer, a positive integer, or zero as the
     * <code>builder</code> has judged the "left-hand" side as less than,
     * greater than, or equal to the "right-hand" side.
     * 
     * @return final comparison result
     * 
     * @since 3.0
     */
    public Integer build() {
        return toComparison();
    }
}
